Introduction

The dispute extends to Zainab, Umm Kulthum and Ruqayyah. Shi'ites believe Fatimah was the only daughter of Khadija whereas Zainab, Ruqayya and Umm Kulthum were the daughters of Khadija's sister, Hala, who had strained relations with her husband and the two girls were brought up by Khadija after the death of Hala. It is notable that before the revelation of the Quran, Muhammad also had an adopted son, that is Zayd ibn Harithah, whose name was changed back from Zayd bin Muhammad to Zayd bin Harithah, after the prohibition of conferring the non-biological father's name to the adopted.[2]

This debate becomes significant and contentious since two of the children, Ruqayyah and Umm Kulthum were consecutively married to Uthman, one after the death of the other, and was thus called Dhul-Nūrayn (Arabic: ذو النورين‎, "He of the Two Lights").[3]

Views

The Quran refers to Muhammad's daughters as his banāṫ (Arabic: بَـنَـات‎, 'daughters').[4][5] There is another argument regarding the explanation of word "Banat" that it does not refer to the immediate daughters, but the female descendants from the line of Fatimah till the Day of Judgment.

Sunni

Sunnis reject the notion of them being born anywhere but in Muhammad's marriage. Sunnis believe that Ruqayyah was born three years after the birth of Zainab, when Muhammad was 33.[3]

Ahmadi agreement

Al-islam.org, an Ahmadiyya[6] website, agrees with the Sunni opinion that Khadijah did indeed have four daughters:

“

Khadija, peace be upon her, was the first woman who believed in the Prophet's divine prophecy. She put all her wealth at his disposal to propagate and promote Islam. Six children were born of his marriage: two sons named Qasim and Tahir who died as infants in Makkah and four daughters named Ruqiyah, Zaynab, Umm Kulthum, and Fatima, who was the most prominent and honoured of them all.[7]

”

Shi'i

Shi'ites believe that Fatimah was Muhammad's only biological daughter.[1] Shia argue it improbable for Khadija to have given birth to so many children at such an advanced age, while having had no children in both her previous marriages. A third version also exists which views the two daughters as being the children of Khadijah's deceased sister, Halah bint Khuwailid.

Shi'ites justify their belief that Fatimah was Muhammad's only biological daughter by referring to the event of Mubahila. Concerning this event, the Quran says:
"But whoever disputes with you in this matter after what has come to you of knowledge, then say: Come let us call abnā’anā (Arabic: أَبـنـاءنـا‎, our sons) and abnā’akum (Arabic: أَبـنـاءكـم‎, your sons) and nisā’anā (Arabic: نِـسـاءنـا‎, our women) and nisā’kum (Arabic: نِـسـاءكـم‎, your women) and anfusanā (Arabic: أَنـفـسـنـا‎, ourselves) and anfusakum (Arabic: أَنـفـسـكـم‎, yourselves), then let us be earnest in prayer, and pray for the curse of Allah on the liars."[Quran3:61(Translated byShakir)]
According to a hadith in Bihar al-Anwar, no woman other than Fatimah was present at the Mubahilah. For this reason, Shi'ites believe that the phrase "our women" in the Quran refers only to Fatimah.[8][9]